Introduction

The Pituriaspida are a small group of fossil, armored jawless vertebrates, only known by two genera, Pituriaspis and Neeyambaspis, from the late Early Devonian or early Middle Devonian (about 390 million years) of Queensland, Australia. The best documented form, however, is only Pituriaspis, which resembles the Osteostraci, although devoid of any median dorsal nasohypophysial opening. The nasal or nasohypophysial opening is supposed to lie ventrally, anteriorly to the mouth. The headshield of Pituriaspis shows a ventral oralobranchial chamber, as in the Osteostraci and Galeaspida, a long anterior rostral process, and two lateral cornual processes which bound anteriorly the area for the attachment of the paired fins. The headshield extends posteriorly to form a long abdominal division which probably reached the anal region.

Pituriaspids lived in a marine, deltaic environment, along with various placoderms.